Define physical quantity .

A physical quantity is a property that can be measured , consisting of a numerical magnitude and a unit .

Why must a physical quantity always be stated with a unit?

The same symbol can represent different quantities, so the unit gives it context. For example, v could mean velocity ( m s -1 ), volume ( m 3 ) or V potential difference ( V ).

All physical quantities consist of a numerical magnitude and a .......... .

All physical quantities consist of a numerical magnitude and a unit .

True or False? A physical quantity is fully described by its numerical value alone.

False. A physical quantity must also include a unit — without it, the numerical value is meaningless.

State the approximate order of magnitude of the diameter of an atom and of atmospheric pressure.

Diameter of an atom ≈ 10 -10 m Atmospheric pressure ≈ 1 × 10 5 Pa

A LevelPhysicsCambridge (CIE)Flashcards1. Physical Quantities & UnitsPhysical Quantities

Physical Quantities (Cambridge (CIE) A Level Physics): Flashcards

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Define physical quantity.

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Define physical quantity.
A physical quantity is a property that can be measured, consisting of a numerical magnitude and a unit.
Why must a physical quantity always be stated with a unit?
The same symbol can represent different quantities, so the unit gives it context. For example, v could mean velocity (m s^-1), volume (m³) or V potential difference (V).
All physical quantities consist of a numerical magnitude and a ...........
All physical quantities consist of a numerical magnitude and a unit.
Estimate the energy required for an adult to walk up a flight of stairs.
Using $Δ E_{p} = m g Δ h$ with mass m ≈ 70 kg, g ≈ 10 N kg^-1 and height Δh ≈ 3 m:
$Δ E_{p} = 70 \times 10 \times 3 = 2100 J$
True or False?
A physical quantity is fully described by its numerical value alone.
False.
A physical quantity must also include a unit — without it, the numerical value is meaningless.
State the approximate order of magnitude of the diameter of an atom and of atmospheric pressure.
- Diameter of an atom ≈ 10^-10 m
- Atmospheric pressure ≈ 1 × 10⁵ Pa

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